<template>
  <div class="box">
    我是子组件A
    <button @click="toB">拨打电话到B</button>
  </div>
</template>
<script>
export default {
  methods: {
    toB () {
      this.$bus.$emit('atob', Date.now())
    }
  }
}
</script>
<style scoped>
.box {
  width: 300px;
  height: 300px;
  background-color: #f00;
}
</style>
